Method of correcting contours of television viewing panels

ABSTRACT

A METHOD OF CORRECTING THE CONTOURS OF THE FACE PLATES OF RECTANGLULAR PRESS-FORMED GLASS VIEWING PANELS FOR TELEVISION PICTURE TUBES PRIOR TO THE REMOVAL OF THE PANELS FROM THEIR FORMING MOLDS. THE METHOD COMPRISES DIRECTING A STREAM OF LOW PRESSURE PRESSURIZED AERIFORM COOLING FLUID INTO THE INTERIOR OF THE PANELS AT A SELECTED AREA OF EACH OF THE FACE PLATES THEREOF AND SUBSTANTIALLY NORMAL TO THE CHORD OF THE CURVATURE OF SAID AREAS OF THE FACE PLATES. THE COOLING EFFECT OF SAID COOLING FLUID CAUSES SAID   PANELS TO SEPARATE FROM THEIR FORMING MOLDS MORE THAN USUAL IN SAID AREA AND THEREBY CHANGE THE SHAPE OR CONTOUR OF THE PANELS.

mach'z, 1971' L- 'A. CARPENTER METHOD OF CORRECTING CONTOURS: OF TELEVISION VIEWING PANELS Filed Sept 16, 1968 E m n U Smww M O K n F FO INVENTOR. Lynn A. Carpenter im AGENT &

United States Patent tfice 3,567,415 Patented Mar. 2, 1971 3,567,415 METHOD OF CORRECTING CONTOURS F TELEVISION VIEWING PANELS Lynn A. Carpenter, State College, Pa, assignor to Corning Glass Works, Corning, N.Y. Filed Sept. 16, 1968, Ser. No. 759,957 Int. Cl. C03b 11/02 US. CI. 65-69 2 Claims ABSTRACT OF THE DISCLOSURE A method of correcting the contours of the face plates of rectangular press-formed glass viewing panels for television picture tubes prior to the removal of the panels from their forming molds. The method comprises directing a stream of low pressure pressurized aeriform cooling fluid into the interior of the panels at a selected area of each of the face plates thereof and substantially normal to the chord of the curvature of said areas of the face plates. The cooling effect of said cooling fluid causes said panels to separate from their forming molds more than usual in said area and thereby change the shape or contour of the panels.

BACKGROUND OF THE INVENTION The present invention relates to a method of differentially cooling selected areas of the face plates of newly formed glass rectangular viewing panels for cathode-ray or television picture tubes to correct a warped condition of such panels commonly termed in the glassmaking industry as diagonal twist. For reasons not entirely understood, the contours of the face plates of panels of the type mentioned often become distorted due to the panels warping or twisting about a pair of their diagonally opposed corners or diagonal axes during the cooling of the panels immediately following the forming thereof. Heretofore, a correction of such distortion of the face plates of such panels was usually accomplished by reforming of the panels following their removal from their forming molds. However, it has long been realized that, if said distortion can be eliminated or minimized prior to the removal of the panels from their molds, that is, during the cooling of the panels in their forming molds, no or only a minimum amount of reforming of the panels would be necessary following their removal from the molds. Accordingly, after a considerable amount of study and experimentation, the method of the present invention was developed to eliminate or minimize the aforesaid distortion.

SUMMARY OF THE INVENTION BRIEF DESCRIPTION OF THE DRAWING The single drawing figure in the case is an isometric view of a viewing panel and its forming mold illustrating the practice of the method of the present invention.

PREFERRED EMBODIMENT OF THE INVENTION Referring to the single drawing figure in detail, there is shown a viewing panel 11 which is still in its forming mold 12 following the press-forming of the panel by a plunger cooperative with said mold but not shown in the drawings for purposes of simplification thereof. Mold 12 is one of a plurality of similar molds which are carried adjacent the outer periphery of the mold carrier or mold table 13 of an indexing turret type of glass pressing machine such as is well known in the art, such machine being successively indexed between glass gob feeding, glass pressing, article cooling and article takeout positions as is also well known in the art. The position which mold 12 is illustrated in the drawing as occupying is preferably the position just prior to the takout position, and mold carrier or table 13 is indexed in a counterclockwise direction as indicated by the arrow in the drawing.

Viewing panel 11 includes, of course, the usual face plate portion 110:, and first and second pairs of opposite corners or opposite diagonal areas of the face plate and viewing panel are designated, respectively, A and B, defining one diagonal axis of panel 11, and C and D, defining the other diagonal axis of the panel. An aeriform pressurized fluid conduit 14 is supported in any convenient manner adjacent the path of rotation of mold table 13 and in the index position just prior to the takeout posi tion as previously mentioned. There is included in conduit 14 a manually actuated valve 16 which is employed for adjusting the amount of flow of pressurized aeriform cooling fluid through the conduit. The first end 14a of conduit 14 is positioned above the index position illustrated so that orifice 14b in the extremity of such first end is disposed directly above corner or area B of viewing panel 11 when mold 12 is in the index position shown. End 14a of conduit 14 is positioned as described so that orifice 14b therein is, for example, approximately 4 inches above the inner surface of face plate 11a of panel 11 when such panel and its forming mold 12 are dwelling in the indeX position illustrated. End 14a is also positioned so that aeriform fluid issues from orifice 14b in a direction substantially normal to the chord of the curvature of the corner or area B of face plate 11a of a panel such as 11. The second end 140 of conduit 14 is connected to a suitable source of pressurized aeriform fluid such as compressed air at a constant pressure of at least 2 p.s.i., for example, such source not being shown in the drawings for purposes of simplification thereof.

In practicing the invention disclosed, valve 16 is adjusted so that the pressurized aeriform fluid in end 14a of conduit 14 is preferably at a pressure of approximately 2 p.s.i. Then as each mold, such as 12, and a formed viewing panel, such as 11, therein is indexed to the position illustrated in the drawing, the aeriform fluid flowing from orifice 14b in the extremity of end 14a of conduit 14 strikes the interior surface of the face plate 11a of the respective panel 11 in the corner or corner area B of such panel and face plate. The stream of aeriform fluid continues to strike said surface of the face plate of the respective panel 11 as long as the respective mold 12 dwells in the position illustrated in the drawing. The source of the aeriform fluid is maintained at a temperature so that the stream striking said surface is preferably at a temperature approximately between and F. Following said dwell period, which may be on the order of 17 seconds for example, the next succeeding mold and the viewing panel contained therein is moved into the position illustrated in the drawing and said stream of air then strikes the interior surface of the face plate of such next succeeding viewing panel in a manner identical to the preceding one. Such operation continues as long as panels are continued to be indexed by the glass-forming machine to the position illustrated. This will be readily apparent to those skilled in the art. 1

It is believed that the following comparison of the contours of the face plates of a pair of viewing panels,

the distortion of a first of which was not and the second of which was corrected by the method of the present invention, will be useful in illustrating the improvement in contour achieved by said inventive method.

The first of said pair of panels was gaged at prescribed points in the corners or corner areas A, B, C and D of the panel and said points deviated, in positive and negative directions from a zero reading, 0.0068 inch, 0.0004 inch, -0.0042 inch and 0.0127 inch, respectively. It is thus seen that the most extreme difference between said points was 0.0195 inch. The second of said pairs of panels was then gaged at prescribed points respectively identical to said gaged points on the first panel and such respective points in the corners or corner areas A, B, C and D of the second panel varied, in positive and negative directions from a zero reading, 0.0063 inch, 0.0023 inch, 0.0046 inch and 0.0011 inch, respectively. In this case the most extreme difference between said points was 0.0074 inch. It is, therefore, readily apparent that the differential cooling of the corner of corner area B of the W second panel, by using the inventive method disclosed, not only changed the contour of the panel to bring corners A and B more closely into agreement with each other but also brought corners C and D more closely into agreement with each other, as well as more closely into agreement both corners A and B. Other gaged points between said points in the corners or corner areas A, B, C and D of the face plate of the second panel were also correspondingly brought more into agreement with the desired optimum contour for the formed panels.

Although there is herein described only one example of the practice of the inventive method disclosed, it is to be understood that such is not to be considered in any way as limiting the scope of the invention but that the exclusive rights sought for the invention disclosed is intended to be lmited only by the spirit and purview of the appended claims.

What is claimed is:

1. The method of correcting the contour of the face plates of press-formed rectangular glass viewing panels for cathode-ray tubes prior to the removal of such panels from their forming molds which are carried adjacent the outer periphery of the mold table of an indexing type of glass pressing machine, such method consisting of di= recting a stream of pressurized aeritorm fluid into a corner area of a first diagonai axis of each viewing panel for a period of time and in a direction substantially normal to the interior surface of the face plate of each respective viewing panel in said corner area, such corner area of each respective viewing panel being the outermost corner area of said first diagonal axis and said fluid differentially cooling each of said viewing panels in said corner area to cause the face plates of the panels to separate from their forming molds more than usual and eliminate or minimize twisting or warping of the panels about their second diagonal axis.

2. The method of minimizing or eliminating warping or twisting of a press-formed viewing panel for a rec tangular glass television picture tube, such warping occurring about one of the diagonal axes of the panel during the cooling of such panel in its forming mold which is carried adjacent the outer periphery of the mold table of an indexing turret type of glass pressing machine, said method consisting of applying for a period of time a stream of pressurized aeriform cooling fluid against and substantially normal to the interior surface of the face plate of said viewing panel and in the corner area of such panel which is the outermost and leading corner area of the panel for the direction of rotation of said mold table of said machine, whereby the face plate of the panel in said corner area is caused to separate from its forming mold more than usual and said warping or twisting is substantially counteracted.

References Cited UNITED STATES PATENTS 7/1916 Gift 65348X 1/ 1968 Reynolds 6584X ARTHUR D. KELLOGG, Primary Examiner U.S. Cl. X.R. 6584, 106, 115 

